Radioactive level of coral reefs in the South China Sea

doi:10.1016/j.marpolbul.2019.03.030

Marine Pollution Bulletin

Volume 142, May 2019, Pages 43-53

https://doi.org/10.1016/j.marpolbul.2019.03.030 Get rights and content

Highlights

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Radioactivity in marine sediments declined from the fringing reefs to atoll reefs.
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Radioactivity was higher in coral skeletons than in marine sediments.
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The average Ra_eq in the atoll reefs was <5% of the world's average Ra_eq.
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An abnormally low ²²⁶Ra/²³⁸U activity ratio (<0.1) occurred in coral reefs.

Abstract

In this study, we examined radioactivity simultaneously in surface marine sediments and coral skeletons collected from 12 locations of the fringing and atoll reefs in the South China Sea. Radioactive level declined from the fringing reefs to atoll reefs because of input of terrigenous minerals in the fringing reefs. Radioactivity was higher in coral skeletons than in marine sediments because of the high ²²⁸Ra activity in coral skeletons. Additionally, an abnormally low ²²⁶Ra/²³⁸U activity ratio (<0.1) of marine sediments in coral reefs was attributed to the biological process of active uptake of ²²⁶Ra and ²³⁸U from seawater by coral polyps rather than the ingrowth process in the ²³⁸U-²³⁰Th-²²⁶Ra decay chain. Several radiological indices were evaluated in coral reefs and significantly lower than recommended values. Particularly, the average Ra_eq in the atoll reefs was <5% of the world's average of Ra_eq. Our results displayed typically radioactive status in coral reefs without close-in fallout of anthropogenic radionuclides.

Graphical abstract

Section snippets

Acknowledgment

The study was financially supported by the National Natural Science Foundation of China (Grant no. 91428203), the Natural Science Foundation of Guangxi Province (2017GXNSFBA198096), Foundation of Key Laboratory of Global Change and Marine-Atmospheric Chemistry (GCMAC1606), the National Key Basic Research Program of China (Grant No. 2013CB956102), and the Bagui Fellowship from Guangxi Province of China. The entire data can be accessed in the text.

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BaselineRadioactive level of coral reefs in the South China Sea

Highlights

Abstract

Graphical abstract

Section snippets

Acknowledgment

Mar. Pollut. Bull.

Sci. Total Environ.

Earth Planet. Sci. Lett.

Cont. Shelf Res.

Mar. Pollut. Bull.

Geochim. Cosmochim. Acta

Atmos. Environ.

Geochim. Cosmochim. Acta

Mar. Pollut. Bull.

Ecol. Econ.

Chemosphere

J. Environ. Radioact.

Appl. Radiat. Isot.

Mar. Pollut. Bull.

Sci. Total Environ.

Sci. Total Environ.

Mar. Pollut. Bull.

Mar. Pollut. Bull.

J. Environ. Radioact.

Mar. Pollut. Bull.

Int. Congr. Ser.

Mar. Pollut. Bull.

Mar. Pollut. Bull.

Mar. Geol.

J. Environ. Radioact.

Chem. Geol.

Quat. Int.

Environ. Pollut.

J. Environ. Radioact.

Baseline
Radioactive level of coral reefs in the South China Sea